Stay-bolt for boilers.



B. E. D. STAFFORD. STAY BOLT POB BOILEBS.

ArrLIoATIon FILED JULY 29, 190s.

Patented Jan. 19,1909.

2 SHEETS-SHEET 1.

Wr/s123555 89 Attorney Patented Jan. 19, 1909.

2 SHEETS-SHEET 2.

` lorney l, WITNESSES UNITED sTATEs PATENT OFFICE...

BENJAMIN E. Di s'rAFFoRD, or PITTsBURG,`-1 ENNsYLvAN IA, AssIGNoR To FLANN'ERY BoL'r COMPANY,v oF'grIrrsBURG, PENNSYLVANIA. l

STAY-BOLT FOR BOILERS.

' 'speeiscation er Letters Patent.

Patented Jan. 179, 1909.

Application mamy 29, ios. sonal No. 445,899.

Llo Aall whom 'it may concern.'

`Be it known that I, BENJAMIN' E. D.

f Improvements in Stay-Bolts for'Boile'rs; and I do -liereby declare the following to be a full,

, the past few years Hexible stay bolts,

.pointed out in the claims.

v n rthe accompanying drawings, Figure 1 is ,nnprovement applied thereto.`

clear, and exact description of the invention,- such4 as will enable Aothers skilled 'in theart to which it appertains to make andl use the same;

Myinventionff relates to an improvement in vmeans for bracing the roof and crown sheetsof boiler-lire "boxes, the object being to Aprovide..connections between the crown and roof Sheets of boilers, that will allow for, and accommodate the forces ofexpansion and'contraction onlines of least resistance, and that will permit of material 20" movement of `the-complete `fire box under expansion and contraction without imparting twistingor bending strains to the stay rods or the sheets to which thel stay rods ar'e attached.

- With these objects in'view my. invention .consists V.in the -parts and combinations of parts as. will be more fully described and a view in section through roof sheet of boiler and crown sheet of re boxv showing my Fig. 2 is a view 1n elevation of a series of pads show- V'ing the-manner of arranging them against the inner face of the roof shee Fig. 3 is asimilar view of a modified form of pad.' Fig. 4 is an enlarged view in section of a section of the construction shown in Fig. 1. Fig. 5 is a view of amodiied form of ad, and Figs. 6 and 7 are views of modifcatlons.

In staying or bracing the inner and outer sheets of boilers it is at present customary to employ either rigid or flexible stay bolts at the sides, and jomted or sectional braces between the roof and crown sheets. lVithin owing to their ability to maintain natural conditions throughout under changeable pressures and temperatures, have practically superseded the rigid bolt at the sides and at some points between the crown and roof sheets. but they have'n'ot, owing to the'difiiculty in applying them,- been employed generally becrown sheet of the fire box.

One of the common formsl of stay bolts now in general use is the Tlite flexible stay bolt, which comprises a bolt threaded atone end for attachment to the inner sheet and vprovided with a rounded head the latter restf ing on a curved seat in a sleeve or bushing, the latter being threaded externally for attachment to the outer sheet of the tire box, and for the attachmentof forms a .steam tight joint This bolt can be readily applied to two sheets that are parallel or nearly so,but it has been .found diflicult to adaptthem to portions of roof sheets, and crown sheets where the sleeves which screw into thecurved roof sheet will rest at an anule to the b'olt,and m improvement is designed particularly for a apting stay bolts of the t e above referred to, to the crown and roo sheets.,

In the drawing Fig. l Ihave shown the Tate 'fiexible bolt v1 connecting the crown i and roof sheets at the sides, and 2 represents the same bolt used in connection with my improved pads or plates 3. These pads are preferably provided with parallel ,sides 4 and pointed ends 5, each end of onefresting betweenthe two ends of the next adjacent two. By this arrangement it is possible to have the securing rivets 6 farther removed from the bolt holes than would be possible with pads having square ends, and thus not only solidly secure the pads to the rootl sheet, but prevent any material weakening of either the pads or the roof sheet. I prefer to provide each pad with either four seats 7 as-shown in Fig. 2, or six seats as shown in Fig. 3, but the number is immaterlal as my mventionl eomprehends broadly the pads secured to the inner face of the roof sheet 8 and provided with one or a lurality of seats. These pads 3 may be ma e of cast steel, compressed steel orhdrop forging, and each is curved to conform to the inner face of the roof sheet 8, and is secured thereto by a series of rivets Each pad is provided with one or more depressed seats 7 having an opening through its bottom for the pas- The seats 7 are curved to conform to the contour ofthe sphericall heads 9 of the bolts 2, while the openings 10' through the bottom of the cap 4which l with the sleeve.V

the seats, are suiii- 'ciently large to permit of the-necessary.

movement of the bolt roof sheet. 8, and are as shown in Fig. 1, ar-j ranged in line with the axes of the bolts,

with relation to the;Y

' The heed 9 of each holt 2, therefore, has e ieA solid bearing inits seat 7 irrespective of its position, the opening in each, being flaring' es shown in Figs. 4 and 5 so as to permit of the necessary movements.

The roor sheet 8 of the boiler is provided with ethreeded hole for each 'stoy bolt 2. These holes are somewhat .larger than the heads of tlievbolts, and are so formed and thrended that the caps ll are radial to the roof sheet, :indio most instances, (except et the 'eenten of the lire boxlwhen the bolts ere substantially' verticel) the cops il rest et en seigle to the bolts 2 es clesrly'shown in Fig'.

' 1. The seats 7 in the pods 3 are always in line with the axes fof the bolts 2 thereby per mitting the ready insertion and Withdrawal of the,holts, and the threaded holes in the roof sheets S are radial to the letter, and so loented with relation to the bolt seats that.

when the cps jll are removed, the bolts may be readily removed and replaced. These nods 3 may he dropdorged es shown in Fig'.- 't or of pressed steel as shown in Fig, .hut in each instance they ere riveted to the inner fece of the roof sheet 8, andere provided with one or e plurality oi seats 7. 'for the spherical heads 9 of the bolts 2,.'end e hell mouth opening l() for the passage o3? the holt through seme, end oooh see-t is closed by the cap ll screwed into e. threeded opening inthe roof sheet, and provided with e conceved lower foce which :forms a beering for the spherical heed or the holt. This construction 'of parts embodies all the-ed venteges of the flexible stay bolts 'new generelly employed for bracing the box et the sides, and in addition, permits, of the use of the bolts at points Where the ordinary stoy bolt cannot be employed.

The stay 'bolts E?, ere threaded et their in- `ner ends andr ere screwed intolthreaded openings in the crown sheet 121er' the fire box and then upset in the usual and well known manner. Y

ln the construction shown in Figs. 6 and 7 llheve shown the enplicetion of the stoy holte 2 to ressed steel `pads 3 strengthened by the bus ing le, the letter being spheri cal externally to conform to the spherical wit in the pad, and spherical internally to forni the sent for the heed 9 of the stay holt 2. f By the application of the bushing l 'produce in eiiect s, large heed, and consequently en increased circumferential hearu ing* against the psd, to withstand. the stresses on the holt.. Again the use of the bashing permits of the use of bolts having heeds that ere not spherical, 'as shown-in Fig. 7.

It is evident that many slight chang-es might be resorted to in the' relative arrangement of ports shown and described Without departing from the spirit end soope of my invention. Hence I would have it understood thet l die not wish to conne myself to the endoso exec-t construction shown and described, but consider myself at liberty to make such slight changes and alterations :is-fairly fall Within the spirit and scope of iny invention.

lJ sving fully described my invention what l olsirn es new and desire to secure by-Letl. rihe combination with inner lend outer sheets the outer sheet having threaded openings, oi pads secured to the inner face of the outer sheet and provided with recessed seats the letter loe-ing open at their bottoms, bolts passing through the seats and having curved heads resting on the seats, the inner ends of the holte secured to the inner lsheets, rand oeps screwed into the openings in the outer sheet.

.2. The combination lwith inner and outer` sheets of a. lire hon the outer sheet having threaded openings, oi pads riveted to the inner 'fece of the outer sheets, each psd lie-' ing provided with a plurality Aol* recessed seats, bolts passing through said 'seats and into the threaded `openings in the outer recessed seats, of bolts having curved heads resting in saidsseats, the inner ends of the bolts being secinfed to the inner sheet, and

v screw 'caps secured Within the threaded openings in the outer sheet and forming aboaring'ior' the heads of' the bolts.

e. in a fire box, the combination with the outer sheet thereof provided with holes, and pads sured to the inner face of said outer sheet, each psd being provided withl a plurslity of recessed seats, each seat registering with s hole Ain the outer sheet, of stay bolts psssing through the pads with their heads resting in the recessed seats thereof, and closures for the holes in the outer sheet.

5. The combination with inner and outer sheets oi o. tire boi; the outer sheet havingeech pad having o plurality of depressed l sente es ch oi' which is in alinement with a, threaded opening in the `outer sheet, of a holt passing through each seat and having a rounded heed resting on the seat and e ce closing the openingsin the outer sheet and fofniing bearings or abutments for the head oi the bolt,

The combination with inner and outer sheets, the outer sheet having threaded openings therein, of e series or abutting ads riveted to the inner fece of the outer s eet eoch psd heving parallel sides and pointed ends, ond each provided. e. plurality of depressed seule, bolts passing through the seats and provided with rounded heads resting on the lader. he inner ends of said bolts being' Secured to the inner shee! and screw rape closing the operiiir-s` in the outer sheets aud forming.:` beni-ingle or abntinente for the headI ol the bolts.

'i'. The Coinlnnaion with inner and outer sheeis, the outer sheet ha ring threaded open- "infine Y therein, pad4 serured lo the inner face el he outer sheet and provided with recessed Seats and a bushing' 'for earh seat, the

said bushingr beinev ,shaped externally lo eorishees. the outer sheer haring threaded 0pen therein, pads ferured to the inner 'face o'lI the outer sheet and provided with reeessed seats, and n bushing for each seat, the said bushings beineY shaped externally to roirl'orni lo the rurxed Surfaces ol the seats and provided with rui-red Seats ior the heads of (he holle'. oli' bolts haring curved heads resting' in .mid bushings, the inner ends of the bolts beingl secured to the inner sheet, and raps screwed ini'o the threaded opening. in the onler sheet.

ln texlilnony \\'hereol, l have signed thi;- speeiliration in the presence of two subserlr in :i' hnesex BFNJAM iN E. l). S'l`f\l `l*`()l'l). ll' itnesses:

llnwiN S. lrci-i, T. J. ODoNNELi.. 

